[Avulsion fracture of the tibial tubercle in adolescents: 22 cases and review of the literature].

PURPOSE OF THE STUDY: Fracture of the anterior tibial tubercle is exceptional in adolescents. The purpose of this work was to better understand the circumstances of such fractures, identify potential complications, and assess outcome of different therapeutic options.

MATERIAL AND METHOD: This was a retrospective analysis of a consecutive series of 22 children with avulsion fracture of the anterior tibial tubercle. The circumstances of the fracture were noted. The Ogden classification was used to establish the radiological type. Associated lesions were also noted as were any complications. Two types of treatment were given: orthopedic or surgical (several types). The functional outcome was assessed at last follow-up.

RESULTS: Mean age at fracture of the anterior tibial tubercle was 13 years (range 12-16) in 14 boys and 7 girls. It occurred after a jump or reception after a jump in 22 of the children. Five patients presented symptomatic homo- or contralateral anterior tibial apophysitis before the accident. The fracture was not displaced (type IA) in ten patients and was treated orthopedically. In twelve patients, the fracture was displaced (type IB, II, or III) and required osteosynthesis. Immobilization was maintained for four weeks on average (range 3-7). Associated lesions were observed in half of the twelve displaced fractures, with five cases of patellar ligament avulsion and three cases of meniscal injury. There were no complications with type IA fractures. For the twelve displaced fractures, complications were observed in seven children: hematoma (n = 2), infrapatellar hypoesthesia (n = 2), complete rupture of the patellar ligament 38 months after surgery (n = 1), recurvatum with leg length discrepancy (n = 1), and stiff knee (n = 1). Mean follow-up was two years (range 9 months-8 years). The functional outcome was excellent in all patients with a non-displaced fracture and in seven of the twelve patients who underwent surgical treatment.

DISCUSSION: Non-displaced fracture of the anterior tibial tubercle I children (type IA) should be considered as a separate entity responding very well to orthopedic treatment. The other cases of displaced fracture generally require surgery which enables an assessment of often associated lesions. The prognosis of displaced fractures of the anterior tibial tubercle is more sever due to the associated lesions and potential complications. We describe the second case of recurvatum and leg length discrepancy following fracture of the anterior tibial tubercle.

CONCLUSION: Displaced fracture of the anterior tibial tubercle in adolescents is often associated with soft tissue injury (patellar ligament, menisci). Surgery is indispensable and provides good functional results.